mike_au Posted October 28, 2009 Share Posted October 28, 2009 I've been asked to make some effects to set off from within an art installation, the problem is that it is made from sheet metal and would probably break apart fairly easily if anything went wrong. The container is a square tower, about 4" to a side and about 3' tall. Do you think that putting a 3" cardboard mortar (1/2" wall) down the middle would be sufficient to contain three 3/4" fountains and possibly a lance? What would you consider a safe distance from something like that? Can anyone suggest any effects that could be used which would minimize the risk of a catastrophic failure? Would I be better of going all lances so the comp has little containment? Or is it all too risky and I should just tell her it can't be done? Link to comment Share on other sites More sharing options...
Ventsi Posted October 28, 2009 Share Posted October 28, 2009 Some water falls might make for a nice effect, AP based of course. Is this inside or outside? Link to comment Share on other sites More sharing options...
mike_au Posted October 28, 2009 Author Share Posted October 28, 2009 Aaah slight problem there. Ammonium compounds aren't terribly common around here. AN is heavily regulated, I've never even seen AP. I have KNO3, KClO4 and I could make a few other nitrates but that is about the limit of my oxidizers. I'm still waiting to hear back about some of the details but I am assuming outside simply because I wouldn't be comfortable with it being in close proximity to people regardless of what I end up putting in it. Link to comment Share on other sites More sharing options...
Arthur Posted October 28, 2009 Share Posted October 28, 2009 Gerbs fountains lances could be interesting, small mines may assist the effect. How robust is the item and how robust is it's surface finish? Could you do something infront or behind the item? Link to comment Share on other sites More sharing options...
mike_au Posted October 28, 2009 Author Share Posted October 28, 2009 It seems reasonably solid, but I'm not confident it would hold up if a large fountain or several small ones were to blow up inside it. I did consider going behind it but it would have to be right up next to it still. I guess that is still better than inside since there will be less confinement. The metal is rusted and she isn't too concerned about making a mess of it so slag, etc isn't an issue. I've just found out that it is likely to be set off during the day, so I'm now considering some smoke b*mbs with a colour changing lance. As long as it isn't too windy I'm hoping the smoke will help reflect the light from the lance. I'll have to do some experiments on the weekend and to see if that actually works. If not then maybe a smoke b*mb+cremora combo and if all else fails methanol + salts for coloured fire. Actually, the smoke b*mb cremora combo might work well, there are some vents/gaps at the bottom of the tower, start with smoke coming out of them (maybe with a red lance to give a burning look) and then have a cremora shoot out the top. My main concern is the metal and the risk of something blowing up and making shrapnel. The smoke mix is relatively safe, as is cremora powder. The lance will probably be based on star compositions and I don't think they are likely to explode. If I were to proof the mortar with say 3-4 times the BP that I will be using to lift the cremora, I think I would feel reasonably confident that it would hold up. Link to comment Share on other sites More sharing options...
Arthur Posted October 28, 2009 Share Posted October 28, 2009 A four inch square tower three feet high will need a very sympathetic and small treatment to be sensible and safe. Look at something like a length of visco or time fuse with occasional sachets of bengal light comp something that just burns and slowly and has colour and smoke. A Joss Stick would be pyro on the scale of that sculpture! Don't overpower the creation with the effect. Link to comment Share on other sites More sharing options...
mike_au Posted October 29, 2009 Author Share Posted October 29, 2009 A four inch square tower three feet high will need a very sympathetic and small treatment to be sensible and safe.You think a 3" cremora is too risky? I think it would probably use about 10-20g of BP to lift it Look at something like a length of visco or time fuse with occasional sachets of bengal light comp something that just burns and slowly and has colour and smoke.Bengal light looks interesting, I might try that. A Joss Stick would be pyro on the scale of that sculpture! Don't overpower the creation with the effect.It is part of a course she is doing, her assignment is to build using metal work tools an installation that includes fire (or something to that effect) so I don't think she is too concerned about drawing attention away from the art, she just wants something impressive compared to everyone else who will just be packing theirs full of wood and lighting it up. Anyway, I will point her to this thread and show her some videos of different effects and she can decide what she wants (the tower looks rather industrial so I still reckon the smoke and cremora would suit it). Link to comment Share on other sites More sharing options...
scarbelly Posted October 29, 2009 Share Posted October 29, 2009 I don't know if it's possible, but a roman candle-like cremora might be cool. With a big puff of flame, then a delay and then another, etc. Link to comment Share on other sites More sharing options...
tentacles Posted October 29, 2009 Share Posted October 29, 2009 (edited) A good solid 3" mortar lifting a creamora should be safe - I suggest a 50/50 mix of airfloat and creamer or AF/powdered sugar.Be sure to have plenty of distance from the audience. As long as your BP is reasonably consistent, short of cramming a cannon ball on top of the creamer charge, I don't see how the tube could develop enough pressure to fail. Just use regular old BP 75/15/10 kno3/c/s, no benzolift or flash or anything else insane. To get a good effect out of a device like this, you'll probably want to do some testing. I'd start at maybe 7g of BP and 250g of charge. If you hit it too hard the fireball will be more of a column of fireand likely noisy besides. If you don't use AF in the mix, especially with creamer, expect to cover everything in the vicinity in caramel from unburned fuel. Load the lift charge in and then stuff an open plastic bag down the tube. Wrap the top of the plastic bag around the outside of the tube, like trash bag, and then tape it around the top. This will ensure the charge leaves the tube in an orderly fashion, really helps the shape of the fireball a great deal and the result will be great every time - if you use a disc or wadding I had inconsistent results. Edited October 29, 2009 by tentacles Link to comment Share on other sites More sharing options...
scarbelly Posted October 29, 2009 Share Posted October 29, 2009 (edited) You may want to angle it upwards at like 45 degrees also if you weren't already planning on something like that. I think it would look a bit better, and be more safe. EDIT: didn't realize the plan was to shoot straight up... I am an idiot Edited October 29, 2009 by scarbelly Link to comment Share on other sites More sharing options...
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